1. Field of the Invention
The present invention relates to a sample treating method and an apparatus, and more particularly to a method and an apparatus for treating samples such as semiconductor element substrates that are to be etched as well as to be anticorrosion-treated.
2. Description of the Prior Art
In etching samples such as semiconductor element substrates having, for example, an aluminum film, an aluminum alloy film, or a multi-film structure consisting of these films and a barrier metal using a plasma of a halogen gas, a problem arises in regard to corrosion when they are exposed to the atmosphere after etching. Therefore, these samples must be anticorrosion-treated in addition to being etched. In order to cope with such requirements, there have heretofore been proposed the following technologies.
Japanese Patent Publication No. 30268/1987 discloses a technology of dry-etching and after-treatment according to which an aluminum film or an aluminum alloy film such as of aluminum-silicon, aluminum-copper, or aluminum-silicon-copper is dry-etched in a vessel using a halogen compound gas which is active, followed by treatment with a plasma of a mixture gas consisting of fluorocarbon and oxygen without taking it out of the vessel.
Further, Japanese Patent Publication No. 12343/1983 discloses a technology which exposes the etched aluminum film or the aluminum alloy film to the fluorination plasma in order to prevent the film etched by using the chlorination plasma from corroding after etching.
According to such technologies, however, it is difficult to remove corrosive matter formed during the etching of the samples and adhesive to the side walls of the patterns. In such prior technologies, furthermore, the substitution reaction (substitution into Al.sub.2 O.sub.3 due to the reaction of, for example, AlCl.sub.3 which is a component of the adherred corrosive matter with, for example, oxygen which is a component of gas plasma in the after-treatment) takes place on the surface layer only of the corrosive matter adhered to the side walls of the pattern, and does not proceed into the adhered corrosive matter. When the samples are exposed to the atmosphere, furthermore, water content in the open air infiltrates into the corrosive adhered matter which is not dense, whereby the reaction takes place between the infiltrated water content and the corrosive adhered matter to form a corrosive component (e.g., hydrochloric acid) that corrodes the samples. According to the conventional technologies, as described above, the samples after etching do not have sufficient resistance against the corrosion. In dealing with modern multi-layer films consisting of aluminum and other materials or aluminum alloy films containing copper, in particular, corrosion develops due to the so-called cell action (aluminum works as an anode), the degree of corrosion is accelerated, and lack of resistance against the corrosion becomes more conspicuous.
Therefore, these samples have generally been anticorrosion-treated by a wet system after etching as disclosed in, for example, Japanese Patent Laid-Open No. 133388/1986. The wet-type anticorrosion treatment makes it possible to remove corrosive matters adhered to the side walls of the pattern of the samples and to increase resistance of the samples against corrosion in the open air after etching.
According to the above-mentioned prior art which anticorrosion-treat the samples based on the wet system after etching, any water content remaining after the wet-type anticorrosion treatment reacts with a component containing, for example, chlorine that remains after the wet-type anticorrosion treatment or reacts with chlorine in the open air to form hydrochloric acid (HCl) which is a corrosive component. Therefore, the samples are corroded after the wet-type anticorrosion treatment. Inevitably, therefore, drying is required after the wet anticorrosion treatment.
Therefore, the conventional are involves the following problems.
(1) An extended period of time (at least wet-type anticorrosion treatment time plus dry treatment time) is required before the anticorrosion treatment of samples is finished after etching, and the throughput decreases.
(2) The cost of the apparatus increases and an increased area is occupied by the apparatus when the samples after etching are anticorrosion-treated using a wet-type anticorrosion treatment apparatus and another dry-treatment apparatus (needing means for conveying the samples between these apparatus as a matter of course).
(3) Apparatus are needed to recover waste liquor from the wet-type anticorrosion treatment and to treat the waste liquor, causing the apparatus to become complex and increasing the cost.